Simply put. I laughed my butt off.
To give a lot of details would spoil the patter and artistry that Piff is putting into his show, so I want to be careful not to tip too much. But let's be honest, I wouldn't be expecting Shakespeare here. We've got a (albeit very talented and funny) magician wearing a dragon suit, so make sure your expectations are set accordingly.
As for his humor. I'd rate it a solid PG-13. Here's why. Piff's not afraid to make fun of anything. Literally anything. With a dry wit which you might just have to think about for a second... While the little ones I'm sure would love to see a man in a dragon costume sometimes holding a little doggie, he's apt to drop a choice word or two. So I'd recommend not taking the younger set to his Vegas show. (Besides, it's freaking-Vegas! Why are you bringing a toddler there anyways, really!)
As for his artistry. Don't let the costume fool you. He's got an amazing talent with sleight of hand, and the small theatre he uses at the Flamingo means you can get right up close to see him. He's seriously that good. To perform comfortably in that intimate of environment is very gutsy for a performer, and speaks to his skill and comfort with his audience.
Finally, after the show stick around. How often do you get to meet a magic dragon after all? Piff signs autographs and poses for photos. If you are like me and go to Vegas to see magic shows, the smart money's on Piff by a longshot.